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Simple Summary: Betaine, a natural by-product of the sugar beet industry, can improve growth performance when fed to production animals, particularly under increased environmental temperatures. While the positive effects of betaine in monogastric species like pigs and poultry are well investigated, efficacy in ruminants is less clear. The increasing severity and frequency of heat events will impact livestock production, and dietary betaine offers a management tool to mitigate these events. This meta-analysis examined the effects of betaine supplementation on milk production, growth performance, and carcass traits of ruminants. The results showed a positive effect of dietary betaine supplementation in lactating dairy cattle, beef cattle, and sheep. These promising results show that dietary betaine supplementation can be utilized to improve productivity in ruminants under both ambient and hot conditions. Betaine improves growth performance and health in monogastric animals under both thermoneutral and heat stress conditions, but results in ruminants have been more equivocal. This meta-analysis investigated the effects of betaine supplementation on productive performance, milk production and composition, and carcass traits of ruminants due to betaine supplementation. A comprehensive search for published studies investigating the effect of betaine was performed using Google Scholar, ScienceDirect, PubMed, and Scopus databases. Effect size analysis, random effects models, I2 statistics, and meta-regression analysis were utilized to assess differences in production parameters. Dietary betaine supplementation increased milk yield (+1.0 kg/d (weighted mean differences presented in this abstract), p < 0.001), dry matter intake (+0.15 kg/d, p < 0.001), and milk lactose (+0.05%, p = 0.010) in dairy cows housed under thermoneutral conditions. In the few studies conducted on small ruminants, there was an increase in milk yield in response to dietary betaine (0.45 kg/d, p = 0.040). Under heat stress conditions or grazing pasture during summer, dietary betaine increased milk yield (+1.0 kg/d, p < 0.001) and dry matter intake (+0.21 kg/d, p = 0.020). Dietary betaine increased final liveweight (+2.33 kg, p = 0.050) and back fat thickness (+0.74 cm, p < 0.001) in beef cattle. Dietary betaine increased final liveweight (0.14 kg, p = 0.010), daily gain (+0.019 kg/d, p < 0.001), and carcass weight (+0.80 kg, p < 0.001) but not backfat in small ruminants. These meta-analyses showed that dietary betaine increases liveweight in small ruminants and beef cattle and increases feed intake and milk yield in dairy cattle. [ABSTRACT FROM AUTHOR]

Simple Summary: As it is the first limiting amino acid, the use of DL-methionine in poultry diet formulation is critical for poultry growth, yet its mode of action is not fully defined. In this study, we conducted two peripheral and central feeding trials to determine the effect of DL-methionine and its analog HMTBa on growth performance, plasma metabolites, and the gene expression of feeding-related hypothalamic neuropeptides in broilers raised to market age (35 d). The study shows for the first time that both sources of methionine share some pathways, but each one has a unique pathway. The present study was designed to evaluate the effects of DL-methionine (DL-Met) 2-hydroxy-4-(methylthio) butanoic acid (HMTBa), or S-(5′-Adenosyl)-L-methionine chloride (SAM), using feeding trial and central administration, on live performance, plasma metabolites, and the expression of feeding-related hypothalamic neuropeptides in broilers raised to a market age (35 d). Final average body weight (BW) and feed conversion ratio (FCR) from the feeding trial exceeded the performance measurements published by the primary breeder. At d35, the MTBHa group had better BW and lower feed intake, which resulted in a better FCR than the DL-Met group at 87 TSAA to lysine. At the molecular levels, the expression of hypothalamic neuropeptide (NPY) and monocarboxylate transporter (MCT) 2 did not differ between all treated groups; however, the mRNA abundances of hypothalamic MCT1 and orexin (ORX) were significantly upregulated in DL-Met- treated groups compared to the control. The ICV administration of SAM significantly reduced feed intake at all tested periods (from 30 to 180 min post injection) compared to the aCSF-treated group (control). The central administration of HMTBa increased feed intake, which reached a significant level only 60 min post administration, compared to the control group. ICV administration of DL-Met slightly increased feed intake compared to the control group, but the difference was not statistically discernable. Quantitative real-time PCR analysis showed that the hypothalamic expression of NPY, cocaine- and amphetamine-regulated transcript, MCT1, and MCT2 was significantly upregulated in the ICV-HMTBa group compared to the aCSF birds. The hypothalamic expression of the mechanistic target of rapamycin (mTOR), AMP-activated protein kinase (AMPKα1), D-amino acid oxidase, and hydroxyacid oxidase was significantly upregulated in DL-Met compared to the control group. The mRNA abundances of ORX were significantly increased in the hypothalamus of both DL-Met and HMTBa groups compared to the aCSF birds; however, mTOR gene expression was significantly downregulated in the SAM compared to the control group. Taken together, these data show, for the first time, that DL-Met and HMTBa have a common downstream (ORX) pathway, but also a differential central pathway, typically NPY-MCT for HMTBa and mTOR-AMPK for methionine. [ABSTRACT FROM AUTHOR]

Simple Summary: Ruminants under grazing conditions play an important role, especially in developing countries. Enteric methane emissions from ruminants are greater with pasture-based diets; however, it is not clear which abatement practices are effective to reduce methane emissions under grazing conditions. The objective of this review was to identify and describe enteric methane abatement practices for ruminants that are applicable under grazing conditions. Decreasing the pre-grazing herbage mass reduced methane emissions per unit of product. Other grazing management practices such as increased stocking rate, decreased forage maturity, rotational stocking, and incorporating tannin-containing or non-tannin-containing legumes showed inconsistent results. Nitrogen fertilization or silvopastoral systems did not modify methane emissions, although they may alter carbon sequestration in a system. Supplementation in grazing conditions shows inconsistent responses on methane emissions. However, lipid supplementation showed promising results. Identifying and implementing grazing strategies and supplementation practices under grazing conditions is required to increase efficiency and reduce the environmental impact of these systems. Ruminants produce approximately 30% of total anthropogenic methane emissions globally. The objective of this manuscript was to review nutritional enteric methane abatement practices for ruminants that are applicable under grazing conditions. A total of 1548 peer-reviewed research articles related to the abatement of enteric methane emissions were retrieved and classified into four categories: non-experimental, in vitro, in vivo confined, and in vivo grazing. The methane abatement strategies for grazing systems were arranged into grazing management and supplementation practices. Only 9% of the retrieved papers have been conducted under grazing conditions. Eight grazing management practices have been evaluated to reduce methane emissions. Decreasing the pre-grazing herbage mass reduced the methane emission per unit of product. Other grazing management practices such as increased stocking rate, decreased forage maturity, rotational stocking, and incorporating tannin-containing or non-tannin-containing feeds showed contradictory results. Nitrogen fertilization or silvopastoral systems did not modify methane emissions. Conversely, supplementation practices in grazing conditions showed contradictory responses on methane emissions. Lipid supplementation showed promising results and suggests applicability under grazing conditions. Identifying and implementing grazing strategies and supplementation practices under grazing conditions is required to increase efficiency and reduce the environmental impact of these systems. [ABSTRACT FROM AUTHOR]

Simple Summary: Practitioners look for specific treatments to solve sub-fertility, which nowadays represents a common challenge in canine reproduction. In human, as well as in veterinary medicine, several dietary protocols have been developed to relieve poor sperm concentration and function. They both are constraining factors of breeding programs. Particularly, food supplementation should include micronutrients and anti-oxidants in balanced amounts, exploiting their synergistic actions. Thus, the cumulative effect of vitamin E, selenium, zinc, folic acid, and n-3 polyunsaturated fatty acids (PUFA) on sperm motility and membrane properties was investigated in healthy normospermic dogs. Results of a 90-day-long supplementation period were compared to a control group, not receiving any dietary integration. The positive results obtained in healthy subjects on sperm motility and membrane properties lead us to consider the opportunity to further use the dietary strategy to improve seminal parameters in sub-fertile dogs, too, as reported for other species. Food supplementation and a balanced diet can be pointed out as cheap and safe alternatives within an innovative multimodal approach to improve reproductive performances in healthy dogs. Sub-fertility represents a common challenge in canine reproduction. Different protocols, supplementing daily given quantities of micronutrients, were investigated to improve poor sperm concentration and/or function, which represent breeding major constraining factors in the canine species. Little information is available for dogs concerning the effect of a daily supplementation with a complex of vitamin E, zinc, selenium, folic acid, and n-3 polyunsaturated fatty acids (PUFA) on semen quality. Thus, the present study investigated this effect on semen motility and sperm membrane properties. Serial semen analyses from fourteen healthy normospermic dogs, fed with the same commercial diet, were performed on Days 0 (T0), 30 (T30), 60 (T60), and 90 (T90). Seven dogs were randomly included in the treatment (T) group, receiving a supplementation of vitamin E, zinc, selenium, folic acid, n-3 PUFA; and seven other subjects composed the control (C) group. Total Sperm Count (TSC), Computer-Assisted Sperm Analysis (CASA) indexes, mortality, and functional membrane integrity were assessed. The ANOVA compared results between groups and sampling times (p < 0.05). From T60, the supplementation significantly improved TSC, progressive motility, functional membrane integrity, and decreased mortality. Present results lead us to consider ameliorative effects of a two-month healthy diet supplementation on canine spermatozoa. The positive effects of the described balanced integration of micronutrients on sperm motility and prevention of oxidative stress should be considered, especially when decreased seminal parameters may result from inadequate intake, reduced absorption, increased losses or demand, or to attenuate the impact of age. [ABSTRACT FROM AUTHOR]